1. Field of the Invention
The present invention relates to the structure of a loading or tail gate hinge device for a vehicle, and in particular to the structure of the loading or tail gate hinge device through which the gate is removably mounted to a loading bed of the vehicle.
2. Description of the Related Art
Conventionally, a hinge for a removable loading or tail gate on a truck is of a type indicated, for example, in Japanese Utility Model Publication of Examined Application No. SHO52-14852, wherein a hinge plate secured to a chassis side and a hinge plate secured to the loading or tail gate side are connected by means of a freely rotatable hinge pin.
On one of these hinge plates, an almost tubular hinge pin support section with a slot parallel to the hinge pin is formed, and for example, the gate together with the other hinge plate and the hinge pin can be removed in the axial direction of the hinge pin only at the time when the gate is opened to the point when it hangs straight down perpendicularly from the truck loading bed, due to the fact that one part of the other hinge plate passes through the slot.
Because such a hinge structure is the type which receives any load on the gate through the pin, it is difficult to apply it to large models because of strength limitations. Therefore, increased strength must be provided through the increased thickness of the hinge plate, and new problems occur such as poor processing characteristics of the plate. In addition, the operation of installing the loading gate is troublesome because of the difficulty of positioning the pin in the axial direction while maintaining the loading gate in position. In addition, connecting pins as well as hinge plates are necessary for the hinge structure, which is undesirable because of the number of parts required.
In order to make it easy to install and remove the gate on the loading bed with this type of conventional device, the fitting parts by which the hinge plate on the loading bed and the hinge pin are engaged to each other, and the engaging parts for both hinge plates and the like, must be provided with a certain degree of play. As a result, when the gate is closed, it is shaky, and shifts in the transverse direction, giving rise to such problems as incomplete engagement of the gate locking device.
In addition, during installation or removal, it is necessary to move the gate horizontally in the axial direction while supporting the weight of the gate. Especially when installing the gate, the tips of the left and right hinge pins which are secured to the gate must be engaged with the hinge pin holding, section on each of the loading bed hinge plates almost simultaneously, so that the installation and removal operations become very troublesome.